Low-power variable impedance load/tuning unit

An impedance tuner is presented which operates over the range 1.8 to 3 GHz. The tuner is suitable for use as either a one-port variable impedance termination or as a two-port tuning element. It employs a broadside coupler and a varactor diode tuned phase shifter and can yield |Gamma_MAX| of nearly 0.9 giving near total coverage of the Smith chart. The power consumption of the whole unit is less than 800 mW, making it suitable for low-power applications. The size of the unit is 23 times 5 mm. Representative tuning and reflection variation are given for 2.2 GHz operation.